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Re: Where are the semantics in the semantic Web services?

From: Ravi Prakash Putchala <praks.putchala@gmail.com>
Date: Mon, 19 Sep 2005 13:36:06 +0530
Message-ID: <e1a781da05091901061cdf1810@mail.gmail.com>
To: "Shi, Xuan" <xshi@geo.wvu.edu>
Cc: Joachim Peer <joachim.peer@unisg.ch>, "'www-ws@w3.org' " <www-ws@w3.org>, "www-ws-request@w3.org " <www-ws-request@w3.org>

HI Xuan,

The work of Guus Schreiber (http://www.cs.vu.nl/~guus/) 
seems to be relevant to what you are raising.



On 9/19/05, Shi, Xuan <xshi@geo.wvu.edu> wrote:
> Dear Dr. Peer:
> Thanks very much for your time and kind attention to my questions. Actually
> I am suspicious about the current research approaches for both SW and SWS..
> According to the definition of "semantic" Web, "semantic" means
> machine-processable, then Web service by default is already "semantic" as
> it's just designed for machines but now it's criticized as "not" semantic!
> Since many people said SWS is SW + WS, then I think we can talk about
> something of SW first. How can we design and define the ontology for color?
> People just use the concept of color by default without defining a color
> ontology, but actually a specific color like "black" can be defined in
> different approaches:
> RGB -> (0 0 0) vs. (0, 0, 0) and more ...
> CYMK -> 0% 0% 0% 100%
> HSV -> 0 0% 0%
> Natural Language -> Black
> Hexadecimal code -> 000000
> All of them has the same meaning while such like "Aqua" and "Cyan" produce
> the same color (e.g. in hex code 00FFFF) or "Fuchsia" and "Magenta" produce
> the same color (e.g. in hex code FF00FF).
> Thus how can SW/OWL/RDF experts use OWL/RDF to define the ontology of color
> that includes those different specifications and relationship? Since the
> datatypes are limited within XML schema, even we have to define "color"
> class as a subclass of "string" which looks ridiculous. In this typical
> case, color is a class and all named/coded color can be the instances of the
> color class. Or we can define "red" as a subclass of class "color" since we
> can define many more different colors like "xxxxx red".
> I will be very grateful to you or any other people in this community if you
> can provide any existing reference to a color ontology defintion. Your kind
> attention and advice will be greatly appreciated.
> Best regards,
> Xuan
> -----Original Message-----
> From: Joachim Peer
> To: Shi, Xuan
> Cc: 'www-ws@w3.org'; www-ws-request@w3.org; Shi, Xuan
> Sent: 9/17/05 5:09 AM
> Subject: Re: Where are the semantics in the semantic Web services?
> hi Xuan,
> > I specially appreciate the "law of the semantic web" as he said by the
> end
> > of the paper "The more agreement there is, the less it is necessary to
> have
> > machine-processible semantics". I think it's the same to semantic Web
> > services.
> >
> My thinking of using "semantic Web services" is that we
> - need to write down a sufficiently large part of the semantics of a
> service using some kind of well defined 'building blocks',
> - that can be assembled using some form of 'semantic glue' to capture
> service semantics.
> The building blocks are domain-specific terms defined in some kind of
> shared ontology (just ANY form of agreed data type definition, IMHO that
> could even be plain XML DTDs),
> The 'semantic glue' is a well defined (logic-based) language that allows
> to take these terms to form sentences like:
> "if the world state statisfies an instance of formula F1 before service
> execution, then the state will satisfy an instance of formula F2 after
> successful execution."
> - the formulas F1 and F2 refer to the agreed domain terms and eventually
> combine them using some kind of logical connectors like AND, OR, NOT
> etc.
> - by "instance of a formula" i refer to the fact that formulas may be
> partially or fully grounded by the input data of the client or the
> output
> of the server (see [1] for details)
> While I also agree with the "law" (or paradox? ;-) of the semantic web
> as
> expressed above, i think that semantic Web services can provide added
> value if they provide a nice and usable form of 'semantic glue' that
> allows people to form statements using their agreed vocabulary.
> > Question 2 still is whether semantic Web technology (RDF/OWL) is
> suitable
> > for semantic Web services? RDF/OWL are good at defining the "nouns"
> not
> > "verbs". We can define one object is a subclass of another object. But
> how
> > can we define one function is a subclass of another function? Such as
> in
> > OWL-S approach, "BookSelling" is a subclass of "SellingService" and
> > "SellingService" is a subclass of the root ontology class "e_Service".
> Do we
> > need to find some other ways to define the relationship of "verbs"?
> i am not sure if one really needs *verbs*. Personally,  i like the idea
> of
> characterizing operations by describing the precondition state and the
> resulting effect state. I think the description (characterization) of
> states does not require verbs, because states are just static snapshots.
> But of course, sometimes one would like to use some form of "past
> passive
> participles" of verbs to describe effects, e.g. for an email sender
> service, one could be tempted to state that the post-execution state
> entails "sent_mail(m, from, to)" (which of course has its roots in the
> verb 'sending').
> BTW - for the practical implementation of semantic Web services i have
> designed an XML based markup language called SESMA [1], which might be
> seen as a subset of OWL-S that is less generic than the latter (all a
> question of using the right tool for the job, personal preferences etc.)
> i have implemeneted several running (protoype) systems using this
> language
> (e.g. [2]), and feel that SESMA is at least very useful if one needs to
> come up with a service description quickly
> cheers!
> Joachim
> [1] http://www.ai.sri.com/WSS2005/final-versions/WSS2005-Peer-Final.pdf
> [2] http://elektra.mcm.unisg.ch/pbwsc/docs/eswc05jpeer.pdf
Received on Monday, 19 September 2005 13:30:09 UTC

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